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Three current paths are proposed, and theoretical analysis and laboratory tests are carried out to investigate the root causes of bearing failure in IGBT inverter-fed locomotives and EMUs. The three types of current paths that run through the drive unit bearings and axle box bearings used on EMUs and electric locomotives are classified as the primary side current path, the main traction system current path, and the current path between the vehicles of the EMU or electric locomotive and the vehicles it hauls. The research found that the EDM current path in the main traction system caused by common mode voltage is distinguished as the main cause resulting in the failure of the bogie motor bearings or the bearings of the load connected to the motor shaft. The cause of common mode voltage is analyzed, and the thresholds of current density and voltage without causing bearing damage are analyzed and presented. The lab tests carried out on the bearings on the main traction system's current path verified that the current path does exist. The proof to identify electric erosion, such as craters and washboards, and corresponding measures to prevent the failure of bogie bearings are proposed. Further research about the other two current paths is urgent and necessary. [ABSTRACT FROM AUTHOR]

Summary: This study presents the evaluation of the heat transfer characteristics and mechanical deformation of new composite material heat sinks using experimental and computational approaches. First, we synthesized a composite material composed of copper (Cu) and graphite (C) with 60 wt% Cu, with higher thermal conductivity and a lower thermal expansion coefficient than pure Cu and aluminum. The composite material was used to fabricate a heat sink integrated with an insulated‐gate bipolar mode transistor (IGBT) module for enhanced heat dissipation from the IGBT. Compared with the pure Cu heat sink, the composite heat sink decreases the average temperature of the IGBT module by approximately 22 K. It also decreases the total deformation of the heat sink caused by thermal expansion of the material by 78% and the equivalent stress by 25.2%. This study introduces a way to use Cu‐C composite materials in many potential applications, such as heat sinks integrated with IGBT inverters. [ABSTRACT FROM AUTHOR]

Thermal factors contributing to the ageing of Insulated Gate Bipolar Transistor (IGBT) inverters were investigated, with special reference to temperature variation as the main source of degradation of the electrical insulations and material layers. The inverter configuration was analysed in order to predict the lifetime based on thermal ageing. Therefore, a lifetime prediction model based on NSGA-II algorithm was implemented to identify optimal design condition as a compromise between the average temperature and total mass of the inverter. The option of either choosing design configuration according to using the device during the entire lifetime or half of the lifetime of the solar panel was the major decision. The research findings would contribute to better adaptation of IGBT inverter-solar panel for grid electricity connectivity in relation to the replacement of the invertor once over the lifetime of the panel. [ABSTRACT FROM AUTHOR]

With the advances of power electronic technology, direct-driven permanent magnet synchronous generators (PMSGs) have increasingly drawn the interest of wind turbine manufacturers. At the present time, a commercial PMSG wind turbine primarily makes use of a passive rectifier followed by an insulated gate bipolar transistor (IGBT) inverter. Although a PMSG wind turbine with two back-to-back voltage source IGBT converters is considered more efficient, it has not been widely adopted by the wind power industry. This paper investigates both the conventional and a novel vector control mechanism for a PMSG wind turbine that has two side-by-side voltage source pulsewidth modulation converters. The proposed approach is based on a direct-current vector control mechanism for control of both machine- and grid-side converters of a PMSG wind turbine. Then, an optimal control strategy is developed for integrated control of PMSG maximum power extraction, reactive power, and grid voltage support controls. A transient system simulation using SimPowerSystem is built to investigate the performance of the conventional and proposed control techniques for the PMSG wind turbine under steady and gusty wind conditions. This paper shows that when using the direct-current vector control structure, a PMSG system has excellent performance in various aspects. [ABSTRACT FROM AUTHOR]

The development of an advanced Insulated Gate Bipolar Transistor (IGBT) has enabled high-frequency switching operation and has improved the performance of PWM inverters for motor drive. However, the IGBT's high rate of dv/dt has adverse effects on motor insulation stress. In many motor drive applications, the inverter and motor are separated, requiring long motor feeds. The long cable contributes high-frequency ringing at the motor terminal and results in high surge voltage which stresses the motor insulation. The inverter output filter and RDC snubber are the conventional method for reducing the surge voltage. In this paper, we propose a new low-loss snubber to reduce the motor terminal surge voltage. The snubber consists of the series connection of chraging/discharging capacitor and the voltage-clamped capacitor. At IGBT turn-off, the snubber starts to operate when the IGBT voltage reaches the voltage-clamped level. Since dv/dt is decreased by snubber operating, the peak level of the surge voltage can be reduced. Also the snubber operates at the IGBT voltage above the voltage-clamped level, and the snubber loss is largely reduced compared with the RDC snubber. The proposed snubber enables reduction of the motor terminal surge voltage with low loss. © 2005 Wiley Periodicals, Inc. Electr Eng Jpn, 150(4): 64–72, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.10378 [ABSTRACT FROM AUTHOR]

System-level thermal modelling of electric drive systems requires simple thermal models coupled with each other by the operation parameters of the drive systems. This paper presents a simple parameterized power loss model for insulated gate bipolar transistor (IGBT) inverters, in which variables are relevant to the powertrain operation conditions and are routinely monitored. Combined with a two-impedance thermal model of the inverter with parameters fitted to the results of computation fluid dynamics (CFD) simulations, the resulted real-time model can provide accurate estimations of the junction temperature. The present power loss model combined with the simple two-impedance thermal model is very suitable to be used in system-level real-time thermal monitoring of an integrated electric drive system. • Simple analytical power loss model is proposed for IGBT module under SVPWM modulation. • Its representation in terms of electric drive operation parameters makes it suitable for integrated drive system modelling. • Temperature-dependent parameters of the power loss model are obtained from the module datasheet. [ABSTRACT FROM AUTHOR]